This invention relates generally to audio signaling devices, and more particularly to audio signaling devices to be used with remote control locking mechanism for motor vehicles.
Many automobiles and other motor vehicles are equipped with remote control devices for locking and unlocking the doors of the vehicle. Such keyless entry remote control devices generally employ a low power radio frequency signal to activate the locking mechanism of the vehicles doors. Infrared signal devices are also used but are less common, in many cases, the remote control simultaneously activates an anti-theft security system.
To engage the remote control unit, the operator simply pushes a button. In some cases, the remote control unit would have two separate buttons for locking and unlocking the vehicle, and in other cases the remote control units have only a single button which both locks and unlocks the vehicle.
While the devices are relatively simple to operate, they do nonetheless have limitations. If a button is pressed with insufficient force, the remote control will not generate the radio signal that is intended to activate the lock mechanism. On units having a single button, it is possible as well to misapply the button so that two separate consecutive signals are generated. A person intending to lock his vehicle can thereby inadvertently unlock it again. On remote controls with two separate buttons for locking and unlocking the vehicle, it is also possible to inadvertently press the wrong button.
Moreover, drivers will from time to time question whether they have remembered to lock their vehicles' doors after parking them and walking some distance away. Many keyless entry remote control devices using radio frequency signals are operable for distances over 100 feet. However, the signal becomes increasingly unreliable with greater distances due to physical obstacles and radio interference.
If an operator can easily see the interior door lock stems of the vehicle he can verify if the remote control device has worked as intended. However, often when the remote control device is used the operator cannot see the interior door lock stems, either because he is too far away or because his view is obstructed.
To help address this problem, vehicle manufacturers have included circuitry into keyless door locking mechanisms such that engaging the remote control will simultaneously cause the vehicle's headlights and taillights to flash and/or cause the vehicle's horn to sound.
While activating the vehicle's headlights and taillights may sometimes be more easily seen than the position of the vehicle's interior door lock stems, if nonetheless suffers from similar drawbacks if the operator's view of the vehicle is blocked, or if he is too far away, particularly in daylight hours when the vehicle lights are less visible.
Sounding of the vehicle's horn does provide in many ways a satisfactory signal so that the operator can verify whether the remote control device has been properly engaged and its signal properly received by the vehicle's locking mechanism. Sounding of the horn can also assist a driver to relocate his vehicle when he returns to a large and crowded parking area. Many individuals from time to time remember only the general vicinity in which they have parked their vehicle. Unless they are able to see it, they may experience some difficulty to know its exact location. Rather than having to search through numerous rows of vehicles, the sounding of the vehicle's horn when its keyless entry remote control is engaged can provide considerable assistance in locating the vehicle.
However, car horns all sound very similar. If two or more vehicle operators concurrently engage their keyless entry remote control devices it may be difficult to distinguish one vehicle's horn from the other. Similarly, when a driver uses the remote control to lock his vehicle while walking away from it, the signal of a horn sounding cannot necessarily be identified as coming from his own vehicle.
In some vehicles equipped with anti-theft security systems, a separate sound source is used to provide a pre-set audio signal such as a beep tone, to indicate activation of the security system by the keyless entry remote control device, rather than the vehicle's horn. Even such audio signals offer little choice or distinctiveness.
Accordingly, it is desirable to have an audible signal that is more readily distinguishable to verify the activation of a particular vehicle's keyless entry remote control mechanism.